A solar power generation system includes a plurality of solar cell modules that are disposed on a roof, a junction box, in which the wiring from the solar cell modules are arranged together into one and from which the DC power from the solar cell modules is supplied to a power conditioner, and the power conditioner that converts the DC power from the junction box to AC power and links the AC power to a system power supply. Various electronic circuits such as a booster circuit, an inverter unit and the like are incorporated in the junction box and the power conditioner. Therefore, waterproofing measures are taken to prevent entry of rainwater into the interior of the junction box and the power conditioner.
A casing for such a type of junction box or power conditioner includes an outer box, a front face of which is open, and a lid that closes the front opening. Waterproofing measures are necessary to prevent entry of rainwater into the casing through gaps between the outer box and the lid.
With an arrangement disclosed in Patent Document 1, an upper surface 102 of an outer peripheral portion, forming a front opening 101 of an outer box 102, has mounted thereto a plate member 103 that protrudes from the upper surface 102 and has a bent guiding portion at the tip, an upper surface 104b of a lid 104 for closing the front opening 101 has mounted thereto an L-shaped plate member 105 that extends so as to protrude downward, and the entry of rainwater into the interior is prevented by surface contact of a surface 103a of the plate member 103 and a surface 105a of the plate member 105 as shown in FIG. 24.
Patent Document 1: Japanese Published Unexamined Patent Application No. 2004-31481 (FIG. 4)